Control Strategy for Helicopter Thermal Management System Based on Liquid Cooling and Vapor Compression Refrigeration

Abstract

With the continuous application of high-power electronic equipment in aircraft, highly efficient heat transfer technology has been emphasized for airborne applications. In this paper, a thermal management system based on an antifreeze liquid cooling loop and a vapor compression refrigeration loop is presented for high-power airborne equipment in a helicopter. The simulation models of the thermal management system are built in order to study its control strategy for the changing flight conditions. The antifreeze-refrigerant evaporator and air-refrigerant condenser are specially validated with the experimental data. A dual feedforward proportion integration differentiation and expert control algorithm are adopted in the inlet temperature of the cold plate and sub-cooling control of the refrigerant by regulating the compressor speed and the fan speed, respectively. A preheating strategy for antifreeze is set up to decrease its flow resistance in cold day conditions. The control strategy for the thermal management system is finally built based on the above control methods. In this paper, two extreme conditions are discussed, including cold and hot days. Both the simulation results show that the superheated, sub-cooling and antifreeze inlet temperature of the cold plate can be controlled at 3 to8 °C, −10 to −3 °C and 18 to22 °C, respectively. Under the same changing flight envelope, the coefficient of performance of the vapor compression refrigeration loop is relatively stable on the cold day, which is about 6, while it has a range of 2.58–4.9 on the hot day.

Parameter Tuning of a Vapor Cycle System for a Surveillance Aircraft

“…Results in recent studies on aircraft VCS [5,12,[21][22][23][24] are presented for control strategies designed for the system and/or components for dynamic simulations of complete aircraft missions. However, in this study the results represent steady-state solutions obtained at operating points 1 and 2.…”

“…A liquid loop system with ethylene glycol (50%) is marked in blue and a vapor cycle system with refrigerant R134 is marked in green, respectively, in Figure 1. Ethylene glycol has been mentioned [18] or used [5,8] as a working fluid in recent studies on aircraft thermal management. Refrigerant R134 was chosen for this study because it is a commonly used refrigerants in studies [5,[21][22][23] and real-life applications of VCS [3] in aircraft in the last 30 years.…”

“…Ethylene glycol has been mentioned [18] or used [5,8] as a working fluid in recent studies on aircraft thermal management. Refrigerant R134 was chosen for this study because it is a commonly used refrigerants in studies [5,[21][22][23] and real-life applications of VCS [3] in aircraft in the last 30 years. The liquid loop system is a single-phase system since in this study ethylene glycol does not change phase.…”

“…In comparison to ACM, VCS are more energy efficient. They do not require a source of high-pressure air from engine bleed air or conventional ram air for operation, for example [2][3][4][5]. The working fluid in VCS undergoes a phase change and therefore VCS have higher transfer rates than non-phase changing cooling systems making them more efficient in weight and volume [6][7][8][9][10][11][12].…”

Optimization Research on the Heat Transfer Capacity of an Aircraft Fuel Thermal Management System

“…Despite these developments, in the design process of a TMS [21][22][23][24][25][26][27][28], the design parameters of each subsystem and related components typically remain constant throughout the flight, Aerospace 2023, 10, 730 2 of 13 directly impacting the system's cooling capacity being limited throughout mission conditions. Moreover, the existing method of optimizing these system design parameters based on TMS task requirements does not improve the heat dissipation capacity and fuel heat sink efficiency from the system design level.…”